Authors:

Helen Hanson(Brown University)

Xi Wang(Brown University)

Ivo Dimitrov(Brown University)

Brian Maranville(NIST)

C. Majkrzak(NIST)

Jing Shi(Brown University)

Mark Laver(NIST)

Xinsheng Ling(Brown University)

It is now widely accepted that the ground state of the vortex matter in
weak-pinning type-II superconductors is a topologically ordered Bragg Glass
(BrG) phase. An unresolved issue is how to access the equilibrium state of
the BrG phase. For example, in some samples, the ZFC (zero-field-cooled)
states are more ordered than that of the FC (field-cooled) states, while in
seemingly similar samples, the opposite is true. In this work, we use
neutron reflectometry in the diffraction mode to measure thin slices of the
bulk vortex state prepared under various thermal-magnetic history. We found
that in a sample with disordered ZFC states, but more ordered FC states, the
vortex matter is highly inhomogeneous. We found that after repeated thermal
annealing, a large domain of the BrG phase exists in the center of the
sample, while the edge vortex matter remains disordered. Our results also
provide additional insight into the disappearance of the peak effect.

*This work is supported by a grant from the US Department of Energy.

To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2010.MAR.D40.9